A major challenge facing the rehabilitation field is the determination of relationships between impairments, functional limitations and disabilities. Biomechanical movement analysis is a key tool for understanding these relationships, and for providing quantitative objective measures of patient status and treatment outcomes. The objective of the proposed research is the enhancement (through advanced visualization and automation techniques) and commercialization of proven movement analysis analytical techniques developed at the National Institutes of Health (NIH). The software package will include the following: an enhanced C3D file format; a Pre-processor module for automated signal processing and event identification and range labeling; a Model Builder module for creating custom biomechanical models (including assistive devices); a Report Builder for designing report formats; and an Analysis Engine for performing six degree- of-freedom inverse dynamics and other analyses. The result will be a complete rehabilitation focused movement analysis software package (Visual3D) that runs on a personal computer (PC) and can be used by rehabilitation researchers, clinicians, and educators working in a wide range of sub-specialties and research areas. In Phase III we will produce the commercial version of the software. We will establish licensing agreements and a marketing strategy. PROPOSED COMMERCIAL APPLICATIONS: There exists a dearth of motion analysis application software capable of meeting the needs of rehabilitation research and patient care professionals. The vast majority of existing tools are platform dependent, custom built, task specific, and/or nor supported programs. Visual3D will be a relatively low cost program capable of analyzing data from any type of target base movement analysis system, and it will run on standard personal computers. Several companies have expressed a sincere interest in obtaining non- exclusive rights to market Visual3D with their motion capture systems. Therefore, the infiltration of this product into new and existing facilities and educational settings worldwide seems highly likely.